Movement determining mechanism



A118. 1944- w. MOKELVEY 2,356,167

MOVEMENT DETERMINING MECHANISM Filed Feb. 26, 1942 l l l2 INVENTOR WILLIAM L. MC KELVEY BY M MZTORNEY Patented Aug. 22, 1944 MOVEMENT DETERMINING MECHANISM William L. McKelvey, East Hempstead, N. Y., as-

signor to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporationoi New York Application February 26, 1942, Serial No. 432,409

11 Claims.

This invention relates to movement determining mechanisms. More particularly, the invention concerns a mechanism by which the extent or degree of mechanical motion in the parts of a given apparatus or device may be confined within predetermined limits or measured at desired constant intervals.

An object of the invention is to provide a selfcontained small mechanical unit of this character which is readily adapted to any desired apparatus with which it may be advantageously employed.

One of the features of the invention resides in the use of two rotatably mounted controlling members for the mechanism which are driven in the same direction at diiTerent rates of speed, the respective members having cooperating elements thereon which engage and, when engaged, coact with a piece in the mechanism which determines the extent of movement of the members.

A further feature of the invention consists in the provision of spaced gears to form the controlling members of the mechanism, the gears be.- ing coaxially arranged with respect to one another and being of different pitch diameters.

Other objects, features and structural details of the invention will be apparent from the following description when read in connection with the accompanying drawing, wherein Fig. 1 is a side elevation of a preferred embodiment of the improved mechanism in which the same serves to limit the extent of motion of a desired part of the apparatus with which it is employed.

Fig. 2 is a cross-section taken on line 2-2 in Fig. 1.

Fig. 3 is an enlarged detail view showing the movably mounted stop engaging element employed in this form of the invention.

Fig. 4 is a schematic view showing different relative positions of the engaging elements on the rotating members or pinions which cooperate with the limit stop to determine the extent of movement of the members.

Fig. 5 is a side elevation view of a modified form of the invention in which the same is employed in measuring constantly spaced intervals in the operation or extent of movement of a desired part of the apparatus with which it is associated.

Fig. 6 is a view similar to Fig. 5 showing the cooperating elements of the rotatable member in an engaged position, and

Fig. 7 is a cross-section taken on line 1-1 in Fig. 6.

With reference to Figs. 1 to 3, inclusive, the improved movement determining mechanism is illustrated as contained on a U-shaped bracket mounting l0. Secured to the sides of the mounting ill are oppositely disposed bearings II and I2 by which two separate rotatable members in the form of gears or pinions I3 and H are arranged with their respective shafts in coaxial relation. In the construction shown, the pinion or rotatable member designated at M has a larger pitch diameter than the gear or member I?! with which it is associated. In order to clarify the description with reference to the claims, member I4 is hereinafter termed the first rotatable gear or pinion while member I3 is termed the second rotatable gear or pinion. The movement determining piece for the mechanism is indicated at IS in this form of the invention, the same being a fixed bracket element mounted directly on the U -shaped frame mounting Ill.

The first rotatable member includes a normally inefiective movable element therein which engages the stop or limit piece IS, in this instance, at either side of the same as shown in Fig. 2. Gear i4 is consequently confined within predetermined limits of operation in this embodiment of the invention and the mechanism thereby limits the extent of motion of a desired part of the apparatus with which it may be employed. The movable element on member [4 is designated at H, the same being situated in an eccentric position in the member I4 in an opening provided therein for this purpose. One end of the element H, which is pin-shaped, includes a positioning flange portion i8 that, in connection with a spring 20, locates the element in a normally ineffective position with respect to the movement determining piece I5. The pin element I1 is shown in an operative or effective position in Fig. 3. The opposite end of the element I1 is rounded at its tip in this instance, and extends in a longitudinal direction along the axis of the pinion towards .the associated gear or rotatable member I3.

Means in the form of a further pin 2| situated on the second member i3 is provided for moving the movable element I! to an effective stop engaging position. Pins i1 and 2i provide relatively movable parts of a two-part cooperating element for the limit piece ii, the end of pin 2| engaging the rounded tip of the movable pin i1 and urging the same in a longitudinal direction against the action of spring 20 to obtain this result. Spring 20 is suitably secured to the side of pinion or rotatable member ll.

The respective members l3 and H are connected by means which rotates the same in like directions within the limits permitted the members by the piece l5. This is accomplished in the present instance by pinions 23 and 24 mounted on a common shaft 25 located in bearings 28 and 21 situated in the base of the bracket mounting piece I0. Pinion 23 meshes with pinionl3 and pinion 24 meshes with pinion ll. The axis of shaft 25 for the gearing connection illustrated is situated in parallel relation to the axis of the coaxially arranged first and second pinions or rotating members. The motion whose extent is to be determined or limited may be introduced by way of the common shaft 25. Because of this fact, these respective shafts are shown in Fig. l as extending exteriorly of the bracket mounting III. For purposes of description it will be as sumed that the motion of the part of the apparatus which is to be limited is introduced into the mechanism by way of the extending portion of the shaft 25, as designated in the drawing at 29.

In considering the operation of the mechanism,

it will be further assumed that the mechanism starts from one of its limiting positions, such as provided by the parts in their dotted line position. in Fig. 2. As shown in this figure, the extended end of pin engages the right-hand side of the stop piece l and prevents further counter-clockwise movement of gear or rotating member l4 in this direction. Shaft 29, however, is permitted to move under the control of the part of the apparatus with which it is employed so that gear or rotating member I4 is free to rotate in a clockwise direction. Movement of gear H in this direction is permitted by the mechanism until the other limiting position is reached, in which the pin I1 engages the limit piece I5 to the left side of the same as indicated in the full line position of the parts in Fig. 2 of the drawing.

Fig. 4 shows diagrammatically different positions of the parts of the mechanism between its respective limit defining positions. The positions I and 5 at the extreme left and right of this figure and in Fig. 2 designate such limit defining positions. For purposes of description in the instant case, gear H has a larger pitch diameter than gear l3 and a proportional relation such as l to 3 is selected between the respective pitch cirpositioned in longitudinal relation by the gears.

From one limiting position of the mechanism, such as indicated in the dottedline position of the parts in Fig. 2, motion may be introduced into the mechanism by way of shaft 29 so that the rotatable members I and l3'move clockwise until the other limiting position is reached. Fig. 4 shows the relative positions of the cooperating pins of the mechanism as this other stop position is approached. In position 2, gear or rotatable member l3 has passed through one complete revolution of travel. When leaving the stop position I, the pin or actuator 2| immediately moves out of engagement with pin H, which is then inefiectively positioned by spring 20. The gears are urged in the same direction at different rates of speed of pinions 24 and 23, the pin l1 lagging behind pin 2| so that when position 2 is reached. pin I1 is removed from pin 2|. As the motion continues and position 2 is reached, in which two revolutions of gear I! have occurred, the respective pins are then removed from each other. In position 4, which represents the parts when a further full revolution of gear l3 has taken place, pin 2| is shownas overtaking the lagging pin I! and is then only 90' removed therefrom. On the fourth complete revolution of rotatable member l3, the pins again come into cooperative engagement and pin I1 is rendered effective to limit against the piece II. This position oi. the parts is clearly shownby the full line positions thereof shown in Fig. 2.

By changing the gear ratios, the radial positions of the pins, or by obtaining the controlled motion through the shaft of either rotatable member l3 or H, considerable latitude in the extent of movement determined by the mechanism can be obtained. It is further obvious that more than two rotatable members could be used in accordance with the teaching of the present invention, as intermediately located gears could be employed between gears I4 and I3, each having its own slidable pin element therein. This would considerably extend the limits of movement permitted by the mechanism.

With reference to Figs. 5 to 7, inclusive, a modification of the mechanism is shown which permits continuous motion of the rotating members in one direction and measures the extent of such motion at predetermined constant intervals. In

this form of the invention a plate 30 is fixed to' one side of gear or rotatable member 3. The plate cooperates with pinion 23 and this assembly of parts is permitted a limited axial movement to the left as viewed in Fig. 5. Spring 3| normally retains the parts in the position illus trated in Fig. 5, in which a clutch means 32 is engaged. The clutch 32 provides a means for disengaging the respective parts of the shaft 25, which is divided in two parts in this instance. The measuring piece for the mechanism may be considered to be the plate or disc 30 in connection with the axially movable shaft of either gear l3 or pinion 23, on which a suitable counting or measuring device can be located and actuated during and by the axial movement of either of these parts. The cooperating elements to effect this result in the instant case are a roller element 34 situated on the plate 30 and a cam piece actuator 35 located on the second rotatable member M. The motion is preferably introduced to the mechanism in this form of the invention by way of the shaft for gear H or the extending shaft of the pinion 24. The mechanism operates in the manner previously described except for the fact that the cam 35 does not limit against the roller 34 but rides over the same to axially displace the gear' l3, pinion 23 and the shafts therefor against the action of spring 3| and simultaneously opens the clutch means 32 during this operation. This instantaneous position of the parts of the mechanism is clearly shown in Figs. 6 and 7, the gear thereafter continuing in the same direction of travel and the other parts immediately reassuming their normal positions, which are retained until the following cooperative action of the roller and cam.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above arranged in spaced coaxial relation to the first member, said first and second members being of different diameters, means for connecting said members for rotation in the same direction, and an actuator on said second rotatable member that engages and axially moves said element into cooperable relation with said piece.

2. The combination in a movement determining mechanism of, a first gear, a movement determining piece for the mechanism, an element on said first gear adapted to cooperate with said piece and mounted for movement in a direction parallei'to the axis of rotation of the gear, a second gear arranged in spaced coaxial relation to the first gear and being of a different diameter than the same, a gearing connection between said respective gears linking the same for rotation in like directions, and an actuator on said second gear that engages and axially moves said element into cooperable relation with said piece.

3. A motion limiting mechanism comprising a first gear, a second gear coaxially arranged with respect to the first gear and being of a different diameter than the same, a fixed stop piece, a normally inefiective element slidably mounted in the first gear, a second element for rendering said normally ineffective element efiective to contact said stop piece, said second element being mounted on the second gear, and a gearing connection for said respective gears facilitating movement of the same in like directions between the limits of travel permitted the mechanism by the stop piece.

4. In a motion limiting mechanism, a limit piece, a first rotatable member having a normally inefiective movable element therein for engaging said limit piece, asecond rotatable member coaxially arranged with respect tothe first rotatable member and being of a different diameter than the same, connecting means for moving said rotatable members in like directions,

and means situated on said second rotatable member for moving said element to an effective,

limit piece engaging position to define the limit of travel of the mechanism.

5. In a motion-limiting mechanism, a first gear, a limit piece for the mechanism, a second gear coaxially arranged with respect to said first gear, said gears being of different diameters, a pair of cooperable elements, a first thereof beingmovably mounted in said first gear and movable into engageable relation to said limit piece, and the second or said pair being fixed on said second gear in a position to engage the first thereof and 'move the same to a limit piece-cooperating position, and means for connecting said gears to provide movement of the same in like directions within the limits of travel provided the mechanism by the limit piece.

6. A motion limiting mechanism of the character recited in claim 5 in which the connecting means for said gears are gears of different pitch diameters mounted on a common shaft, the axis of which parallels the axes of the coaxial first and second gears, and in which the first of said cooperable elements is normally ineilectively positioned by means of a spring.

7. A motion limiting mechanism as claimed in claim 4, in which the respective rotatable mem-- bers are gears and the first has a larger pitch diameter than the second.

8. A motion limiting mechanism as claimed in claim 4, in which the permitted motion' is introduced therein by way of the first rotatable member.

9. A motion limiting mechanism as claimed in claim 4, in which the permitted motion is introduced therein by way of one or said rotatable members.

10. A motion limiting mechanism as claimed in claim 4, in which the permitted motion is introduced therein by way of the connecting means for moving the rotatable members.

11. In motion-limiting mechanism of the character described, a plurality of rotatably mounted members, motion-limiting means, a pair of cooperable means, a first means thereof being movably supported on a first of said members and movable into engageabie relation to said limiting means, and the second means of said pair being mounted to rotate with a second of said members in cooperable relation to said first means and being adapted to move said first means into engageable relation to said limiting means, and means for rotating said first and second members in the same direction but at ditlerent speeds.

WILLIAM L. McKELVEY. 

